Adaptive headlamp system for vehicle

ABSTRACT

A vehicle headlamp system includes a vehicle supported power and control system including a data bus. A sensor module can be connected to the data bus to provide information related to environmental conditions or information relating to presence and position of other vehicles and pedestrians. A separate headlamp controller can be connected to the vehicle supported power and control system and the sensor module through the bus. The headlamp controller can include an image frame buffer that can refresh held images at greater than 30 Hz speed. An active LED pixel array can be connected to the headlamp controller to project light according to a pattern and intensity defined by the image held in the image frame buffer and a standby image buffer can be connected to the image frame buffer to hold a default image.

CROSS REFERENCE TO RELAYED APPLICATIONS

This application claims benefit of priority to European PatentApplication No. 18201763.2 filed Oct. 22, 2018 and to U.S. ProvisionalPatent Application No. 62/729,298 filed Sep. 10, 2018, each of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to a system providing dynamiclighting control for vehicle headlamps. In certain embodiments, thesystem can be LED pixel array able to provide an intensity and spatiallymodulated light projection suitable for adaptive driving beam systems.

BACKGROUND

A night-time vehicle driver may use a low directed headlight beampattern to prevent drivers of oncoming vehicles from being dazzled orsubjected to safety impairing glare, while switching to a high directedbeam with greater range for improved roadway illumination when oncomingvehicles are not present. However, a driver of the vehicle caninadvertently drive with the high directed beam pattern if they fail tosee an oncoming vehicle. Fortunately, widespread availability of sensortechnologies for driver assist or autonomous operation have also enabledsystems that provide active control of vehicle headlamp roadillumination. Instead of relying on a fixed or user controlledillumination pattern, a headlight beam can be automatically dimmed orredirected based on inputs from the vehicle and/or its surroundings. Forexample, oncoming vehicles can be identified, and a portion of theheadlight beam redirected to limit potential glare. As another example,pedestrian detection or location positioning systems can be used toidentify areas likely to have pedestrians, and headlight beamsredirected to illuminate pedestrian activity. Such adaptive driving beam(ADB) systems have been developed using mechanical shields, LEDs,digital micromirrors, and LCD shuttering systems.

Unfortunately, supporting large active arrays of LEDs or other lightemitter/redirection systems (e.g. digital micromirrors or scanninglasers) can be difficult. Individual light intensity of thousands ofpixels may need to be controlled at refresh rates of 30-60 Hz. Systemsable to reliably handle such data rates are needed.

SUMMARY

In one embodiment, a vehicle headlamp system includes a vehiclesupported power and control system including a data bus. A sensor modulecan be connected to the data bus to provide information related toenvironmental conditions (e.g. time of day or weather conditions) orinformation relating to presence and position of other vehicles andpedestrians. A separate headlamp controller can be connected to thevehicle supported power and control system and the sensor module throughthe bus. The headlamp controller can include an image frame buffer thatcan refresh held images at greater than 30 Hz speed. An active LED pixelarray can be connected to the headlamp controller to project lightaccording to a pattern and intensity defined by the image held in theimage frame buffer and a standby image buffer can be connected to theimage frame buffer to hold a default image.

In one embodiment, the vehicle supported power and control systemprovides image data to the headlamp controller. Alternatively, imagescan be generated by the headlamp controller in response to data receivedfrom the vehicle supported power and control system. In operation, theLED pixel array can be directed to reduce light emitted toward anoncoming vehicle.

In some embodiments, each pixel in the LED pixel array is addressable,while in other embodiments, fixed pixel groupings (e.g. 5×5 pixelblocks) are addressable. The aspect ratio of the LED pixel array can beselectable. In some embodiments the LED pixel array is positionedadjacent to static LED lighting.

In some embodiments the frame buffer is connected to the active LEDpixel array through a pulse width modulator. To be able to timelyrespond to changes in lighting requirements for vehicles moving athighway speeds, the image frame buffer can refresh held images at 60 Hzor greater speed.

In another embodiment, a headlamp controller (suitable for working inconjunction with a vehicles power and sensor system) can include animage frame buffer that can refresh held images at greater than 30 Hzspeed. The headlamp controller can be connected to an active LED pixelarray with individually addressable pixels connected to the headlampcontroller to project light according to a pattern and intensity definedby the image held in the image frame buffer. In some embodiment astandby image buffer can be connected to the image frame buffer to holda default image.

In another embodiment, a headlamp control system includes a headlampcontroller connectable to a vehicle supported power, sensor, and controlsystem through a data bus, the headlamp controller having an image framebuffer that can refresh held images at greater than 30 Hz speed. Anactive LED pixel array connected to the headlamp controller can be usedto project light according to a pattern and intensity defined by theimage held in the image frame buffer. A standby image buffer can beconnected to the image frame buffer to hold a default image. Imagepatterns can be provided in response to sensor information from thevehicle supported power, sensor, and control system, or alternatively orin addition, at least in part in response to local sensor information.

In another embodiment a vehicle headlamp system includes a headlampcontroller having an image frame buffer that can refresh held images atgreater than 30 Hz speed with images to the image frame buffer beingprovided by at least one of a vehicle supported power, sensor, andcontrol system through a vehicle data bus and a local image creationmodule through a local data connection. An active LED pixel array withindividually addressable pixels connected to the headlamp controller canbe used to project light according to a pattern and intensity defined bythe image held in the image frame buffer. Image patterns can be providedin response to sensor information from the vehicle supported power,sensor, and control system, or alternatively or in addition, at least inpart in response to local sensor information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating illumination of a road in discretesectors using an active headlamp;

FIG. 2 illustrates a dynamic pixel addressable lighting modulepositioned adjacent to a static lighting module;

FIG. 3A is one embodiment of a vehicle headlamp system for controllingan active headlamp;

FIG. 3B is one embodiment of a vehicle headlamp system for controllingan active headlamp with connections to vehicle processing output; and

FIG. 4 is a schematic illustration of one embodiment of an activeheadlamp controller.

DETAILED DESCRIPTION

Light emitting pixel arrays may support applications that benefit fromfine-grained intensity, spatial, and temporal control of lightdistribution. This may include, but is not limited to, precise spatialpatterning of emitted light from pixel blocks or individual pixels.Depending on the application, emitted light may be spectrally distinct,adaptive over time, and/or environmentally responsive. The lightemitting pixel arrays may provide pre-programmed light distribution invarious intensity, spatial, or temporal patterns. The emitted light maybe based at least in part on received sensor data and may be used foroptical wireless communications. Associated optics may be distinct at apixel, pixel block, or device level. An example light emitting pixelarray may include a device having a commonly controlled central block ofhigh intensity pixels with an associated common optic, whereas edgepixels may have individual optics. Common applications supported bylight emitting pixel arrays include video lighting, automotiveheadlights, architectural and area illumination, street lighting, andinformational displays.

Light emitting pixel arrays may be used to selectively and adaptivelyilluminate buildings or areas for improved visual display or to reducelighting costs. In addition, light emitting pixel arrays may be used toproject media facades for decorative motion or video effects. Inconjunction with tracking sensors and/or cameras, selective illuminationof areas around pedestrians may be possible. Spectrally distinct pixelsmay be used to adjust the color temperature of lighting, as well assupport wavelength specific horticultural illumination.

Street lighting is an important application that may greatly benefitfrom use of light emitting pixel arrays. A single type of light emittingarray may be used to mimic various street light types, allowing, forexample, switching between a Type I linear street light and a Type IVsemicircular street light by appropriate activation or deactivation ofselected pixels. In addition, street lighting costs may be lowered byadjusting light beam intensity or distribution according toenvironmental conditions or time of use. For example, light intensityand area of distribution may be reduced when pedestrians are notpresent. If pixels of the light emitting pixel array are spectrallydistinct, the color temperature of the light may be adjusted accordingto respective daylight, twilight, or night conditions.

Light emitting arrays are also well suited for supporting applicationsrequiring direct or projected displays. For example, warning, emergency,or informational signs may all be displayed or projected using lightemitting arrays. This allows, for example, color changing or flashingexit signs to be projected. If a light emitting array is composed of alarge number of pixels, textual or numerical information may bepresented. Directional arrows or similar indicators may also beprovided.

Vehicle headlamps are a light emitting array application that requireslarge pixel numbers and a high data refresh rate. Automotive headlightsthat actively illuminate only selected sections of a roadway can used toreduce problems associated with glare or dazzling of oncoming drivers.Using infrared cameras as sensors, light emitting pixel arrays activateonly those pixels needed to illuminate the roadway, while deactivatingpixels that may dazzle pedestrians or drivers of oncoming vehicles. Inaddition, off-road pedestrians, animals, or signs may be selectivelyilluminated to improve driver environmental awareness. If pixels of thelight emitting pixel array are spectrally distinct, the colortemperature of the light may be adjusted according to respectivedaylight, twilight, or night conditions. Some pixels may be used foroptical wireless vehicle to vehicle communication.

One high value application for light emitting arrays is illustrated withrespect to FIG. 1 , which shows potential roadway illumination pattern100 for a vehicle headlamp system illuminating a region 120 in front ofa vehicle. As illustrated, a roadway 110 includes a left edge 112, aright edge 114, and a centerline 116. In this example, two major regionsare illuminated—a downward directed statically illuminated region 122and a dynamically illuminated region 130. Light intensity within region130 can be dynamically controlled. For example, as an oncoming vehicle(not shown) traveling between centerline 116 and left edge 112 movesinto a subregion 132, light intensity can be reduced or shut offcompletely. As the oncoming vehicle moves toward subregion 134, a seriesof subregions (not shown) can be defined to also have reduced lightintensity, reducing the chance of unsafe dazzle or glare. As will beappreciated, in other embodiments, light intensity can be increased toaccentuate road signs or pedestrians, or spatial illumination patternsadjusted to allow, for example, dynamic light tracking of curvedroadways.

FIG. 2 illustrates a positioning of lighting modules 200 able to providea lighting pattern such as discussed with respect to FIG. 1 . An LEDlight module 222 can include LEDS, alone or in conjunction with primaryor secondary optics, including lenses or reflectors. To reduce overalldata management requirements, the light module 222 can be limited toon/off functionality or switching between relatively few light intensitylevels. Pixel level control of light intensity is not necessarilysupported.

Positioned adjacent to LED light module 22 is an active LED array 230.The LED array includes a CMOS die 202, with a pixel area 204 andalternatively selectable LED areas 206 and 208. The pixel area 204 canhave 104 rows and 304 columns, for a total of 31,616 pixels distributedover an area of 12.2 by 4.16 millimeters. The selectable LED areas 206and 208 allow for differing aspect ratios suitable for different vehicleheadlamps or applications to be selected. For example, in one embodimentselectable LED area 206 can have a 1:3 aspect ratio with 82 rows and 246columns, for a total of 20,172 pixels distributed over an area of 10.6by 4 millimeters. Alternatively, selectable LED area 208 can have a 1:4aspect ratio with 71 rows and 284 columns, for a total of 20,164 pixelsdistributed over an area of 12.1 by 3.2 millimeters. In one embodiment,pixels can be actively managed to have a 10-bit intensity range and arefresh rate of between 30 and 100 Hz, with a typical operationalrefresh rate of 60 Hz or greater.

FIG. 3A illustrates an embodiment of a vehicle headlamp system 300including a vehicle supported power (302) and control system including adata bus (304). A sensor module 306 can be connected to the data bus 304to provide data related to environment conditions (e.g. time of day,rain, fog, ambient light levels, etc), vehicle condition (parked,in-motion, speed, direction), or presence/position of other vehicles orpedestrians. A separate headlamp controller 330 can be connected to thevehicle supported power and control system.

The vehicle headlamp system 300 can include a power input filter andcontrol module 310. The module 310 can support various filters to reduceconducted emissions and provide power immunity. Electrostatic discharge(ESD) protection, load-dump protection, alternator field decayprotection, and reverse polarity protection can also be provided bymodule 310.

Filtered power can be provided to a LED DC/DC module 312. Module 312 canbe used only for powering LEDs, and typically has an input voltage ofbetween 7 and 18 volts, with a nominal 13.2 volts. Output voltage can beset to be slightly higher (e.g. 0.3 volts) than LED array max voltage asdetermined by factory or local calibration, and operating conditionadjustments due to load, temperature or other factors.

Filtered power is also provided to a logic LDO module 314 that can beused to power microcontroller 322 or CMOS logic in the active headlamp330.

The vehicle headlamp system 300 can also include a bus transceiver 320(e.g. with a UART or SPI interface) connected to microcontroller 322.The microcontroller 322 can translate vehicle input based on orincluding data from the sensor module 306. The translated vehicle inputcan include a video signal that is transferrable to an image buffer inthe active headlamp module 324. In addition, the microcontroller 322 canload default image frames and test for open/short pixels during startup.In one embodiment, a SPI Interface loads an image buffer in CMOS. Imageframes can be full frame, differential or partial. Other microcontroller322 features can include control interface monitors of CMOS status,including die temperature, as well as logic LDO output. In someembodiments, LED DC/DC output can be dynamically controlled to minimizeheadroom. In addition to providing image frame data, other headlampfunctions such as complementary use in conjunction with side marker orturn signal lights, and/or activation of daytime running lights can alsobe controlled.

FIG. 3B illustrates one embodiment of various components and modules ofa vehicle headlamp system 330 capable of accepting vehicle sensor inputsand commands, as well as commands based on headlamp or locally mountedsensors. As seen in FIG. 3B, vehicle mounted systems can include remotesensors 340 and electronic processing modules capable of sensorprocessing 342. Processed sensor data can be input to various decisionalgorithms in a decision algorithm module 344 that result in commandinstructions or pattern creation based at least in part on varioussensor input conditions, for example, such as ambient light levels, timeof day, vehicle location, location of other vehicles, road conditions,or weather conditions. As will be appreciated, useful information forthe decision algorithm module 344 can be provided from other sources aswell, including connections to user smartphones, vehicle to vehiclewireless connections, or connection to remote data or informationresources.

Based on the results of the decision algorithm module 344, imagecreation module 346 provides an image pattern that will ultimatelyprovide an active illumination pattern to the vehicle headlamp that isdynamically adjustable and suitable for conditions. This created imagepattern can be encoded for serial or other transmission scheme by imagecoding module 348 and sent over a high speed bus 350 to an imagedecoding module 354. Once decoded, the image pattern is provided to theuLED module 380 to drive activation and intensity of illuminationpixels.

In some operational modes, the system 330 can be driven with default orsimplified image patterns using instructions provided to a headlampcontrol module 370 via connection of the decision algorithm module 344through a CAN bus 352. For example, an initial pattern on vehicle startmay be a uniform, low light intensity pattern. In some embodiments, theheadlamp control module can be used to drive other functions, includingsensor activation or control.

In other possible operational modes, the system 330 can be driven withimage patterns derived from local sensors or commands not requiringinput via the CAN bus 352 or high speed bus 350. For example, localsensors 360 and electronic processing modules capable of sensorprocessing 362 can be used. Processed sensor data can be input tovarious decision algorithms in a decision algorithm module 364 thatresult in command instructions or pattern creation based at least inpart on various sensor input conditions, for example, such as ambientlight levels, time of day, vehicle location, location of other vehicles,road conditions, or weather conditions. As will be appreciated, likevehicle supported remote sensors 340, useful information for thedecision algorithm module 364 can be provided from other sources aswell, including connections to user smartphones, vehicle to vehiclewireless connections, or connection to remote data or informationresources.

Based on the results of the decision algorithm module 364, imagecreation module 366 provides an image pattern that will ultimatelyprovide an active illumination pattern to the vehicle headlamp that isdynamically adjustable and suitable for conditions. In some embodiments,this created image pattern does not require additional imagecoding/decoding steps but can be directly sent to the uLED module 380 todrive illumination of selected pixels.

FIG. 4 illustrates one embodiment of various components and modules ofan active headlamp system 400 such as described with respect to activeheadlamp 324 of FIG. 3A. As illustrated, internal modules include an LEDpower distribution and monitor module 410 and a logic and control module420.

Image or other data from the vehicle can arrive via an SPI interface412. Successive images or video data can be stored in an image framebuffer 414. If no image data is available, one or more standby imagesheld in a standby image buffer can be directed to the image frame buffer414. Such standby images can include, for example, an intensity andspatial pattern consistent with legally allowed low beam headlampradiation patterns of a vehicle.

In operation, pixels in the images are used to define response ofcorresponding LED pixels in the pixel module 430, with intensity andspatial modulation of LED pixels being based on the image(s). To reducedata rate issues, groups of pixels (e.g. 5×5 blocks) can be controlledas single blocks in some embodiments. High speed and high data rateoperation is supported, with pixel values from successive images able tobe loaded as successive frames in an image sequence at a rate between 30Hz and 100 Hz, with 60 Hz being typical. In conjunction with a pulsewidth modulation module 418, each pixel in the pixel module can beoperated to emit light in a pattern and with an intensity at leastpartially dependent on the image held in the image frame buffer 414.

In one embodiment, intensity can be separately controlled and adjustedby setting appropriate ramp times and pulse width for each LED pixelusing logic and control module 420 and the pulse width modulation module418. This allows staging of LED pixel activation to reduce powerfluctuations, and to provide various pixel diagnostic functionality.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims. It is also understood that other embodiments of this inventionmay be practiced in the absence of an element/step not specificallydisclosed herein.

The invention claimed is:
 1. A method for providing images to a vehicleheadlamp of a vehicle, the method comprising: providing power to aheadlamp controller via a power bus; providing data to the headlampcontroller via a data bus; providing sensor signals of the vehicle tothe headlamp controller from a sensor module via the data bus;refreshing image data stored in an image frame buffer of the headlampcontroller at a rate of greater than 30 Hz; determining whether toprovide to a light emitting diode (LED) array default image data storedin a standby image buffer instead of the image data stored in the imageframe buffer; and projecting light from the LED array, which is coupledto the headlamp controller, according to a pattern and intensity definedby the image frame buffer or standby image frame buffer.
 2. The methodof claim 1, further comprising identifying an oncoming vehicle andselecting an image to be sent to the headlamp controller using signalsfrom the sensor module.
 3. The method of claim 2, further comprising, inresponse to identifying the oncoming vehicle, the headlamp controllerdirecting the LED array to reduce light emitted toward the oncomingvehicle.
 4. The method of claim 1, further comprising the headlampcontroller controlling the light projected from the LED array usingindividual addressing of each pixel in the LED array.
 5. The method ofclaim 1, further comprising the headlamp controller selecting an aspectratio of the LED array.
 6. The method of claim 1, wherein the LED arrayis positioned in the vehicle adjacent to static LED lighting in thevehicle.
 7. The method of claim 1, further comprising the headlampcontroller controlling the light projected from the LED array using apulse width modulator coupled between the image frame buffer and the LEDarray.
 8. The method of claim 7, further comprising setting ramp timesand pulse width for each pixel of the LED array using a logic andcontrol module and the pulse width modulator in the headlamp controllerto individually control intensity of light emitted from each pixel. 9.The method of claim 8, further comprising staging pixel activation toreduce power fluctuations in the LED array.
 10. The method of claim 1,further comprising the headlamp controller controlling groups of pixelsof the LED array to control the light emitted by the LED array.
 11. Anillumination system comprising: a controller including: an image framebuffer configured to store image frame buffer data, the image framebuffer data configured to be refreshed at a rate greater than 30 Hz, anda standby image buffer coupled to the image frame buffer, the standbyimage buffer configured to store sets of default image data, thecontroller configured to use one set of default image data in responseto a predetermined set of conditions being met; and a light emittingdiode (LED) array connected to the controller to project light accordingto a pattern and intensity corresponding to the image frame buffer dataor the one set of default image data, pixels of the LED array beingindividually addressable such that the pixels are selectivelycontrollable individually and in blocks of pixels.
 12. The illuminationsystem of claim 11, wherein the controller is coupled to a power andcontrol system through a data bus that provides external image data tothe image frame buffer as the image frame buffer data, the externalimage data being used by the LED array to project the light in responseto the predetermined set of conditions not being met.
 13. Theillumination system of claim 11, wherein: the controller is coupled to apower and control system through a data bus that provides sensor signalsfrom an external sensor module, and the controller is configured toidentify positions of objects within a range of illumination of the LEDarray based on the sensor signals and determine from the positionswhether the predetermined set of conditions have been met.
 14. Theillumination system of claim 13, wherein: the controller is configuredto control the image frame buffer and standby image frame buffer to loadthe one set of default image data in response to a determination thatthe object is a vehicle, and the LED array is configured to emit lightthat corresponds to a legally allowed low beam headlamp radiationpattern in response to being driven using the one set of default imagedata.
 15. The illumination system of claim 11, wherein the controller isconfigured to select an aspect ratio of the LED array based on thepredetermined set of conditions.
 16. The illumination system of claim15, wherein the LED array is positioned adjacent to static LED lightingthat is configured to emit light independent of the predetermined set ofconditions.
 17. The illumination system of claim 11, wherein: thecontroller further comprises a pulse width modulator coupled to theimage frame buffer and the LED array, the pulse width modulator isconfigured to drive the LED array based on the image frame buffer datafrom the image frame buffer, and the controller is configured toseparately control intensity of light emitted by each pixel by settingramp times and pulse width of a pulse from the pulse width modulatorindependently for each pixel.
 18. A compound semiconductor metal oxide(CMOS) backplane comprising: a processor; an image frame bufferconfigured to store image frame buffer data, the image frame buffer dataconfigured to be refreshed at a rate greater than 30 Hz and controlledby the processor; a standby image buffer coupled to the image framebuffer, the standby image buffer configured to store sets of defaultimage data, the processor configured to control the image frame bufferand the standby image buffer to provide the image frame buffer data fromthe image frame buffer based on a determination of whether at least oneobject is within a range of illumination of an light emitting diode(LED) array, the image frame buffer data selected between external imagedata received at the image frame buffer and one of the sets of thedefault image data sent to the image frame buffer from the standby imageframe buffer, selection of the one of the sets of the default image dataand transmission of the one of the sets of the default image datacontrolled by the processor; and a pulse width modulator coupled to theimage frame buffer and the processor, the pulse width modulatorconfigured to drive the LED array to emit an image based on the imageframe buffer data from the image frame buffer.
 19. The CMOS backplane ofclaim 18, wherein the processor is configured to separately controlintensity of light emitted by each pixel of the LED array by settingramp times and pulse width of a pulse from the pulse width modulatorindependently for each pixel.
 20. The CMOS backplane of claim 18,wherein the controller is configured to control the image frame bufferand standby image frame buffer to load the one set of default image datain response to a determination that the object is a vehicle, and the oneset of default image data corresponds to emission by the LED array of alegally allowed low beam headlamp radiation pattern in response to beingdriven using the one set of default image data.